High vacuum electron tube



March 27 1934. c. EDELMANN 1,952,493.

HIGH VACUUM ELECTRON TUBE Filed Feb. 3, 1927 CHRIST OPH EDELMANNINVENTOP.

M HT

Patented Mar. 27, 1934 UNITED STATES PATENT OFFICE Application February3, 1927, Serial No. 165,542 In Germany February 5, 1926 2 Claims.

This invention relates to a high vacuum elec-- tron tube for wirelesscommunications and the like composed of the usual anode, cathode and id.

5 In customary structures of this type the anode is constituted by amore or less flat surface, usually in the form of a cylinder, and istherefore at all points equidistant from the cathode.

The anode current depends, aside from the anode potential, on thespacing between the anode and the cathode, and, owing to thecharacteristics of the electron stream, particularly on the size of theanode surface. The anode current depends on the number of electronswhich the anode can simultaneously receive.

In prior structures, when it was desired to increase the anode surface,the spacing between the anode and cathode had to be increased, which inturn necessitated an increase in the anode potential.

According to the present invention, the anode surface is increasedwithout increasing the spacing between the anode and the cathode andwithout increasing the anode potential. This is accomplished byproviding steps or projections on the anode pointing in the direction ofthe cathode, said projections or steps being preferably of differentlengths. In this manner the electron n stream will be subdivided anddistributed. The

" appreciable increase of the anode surface thus obtained willbeneficially affect the harmful space charge.

The drawing represents schematically an exemplification of the inventionin which a is the tube, 0 the cathode which, in the usual manner, isconnected with a battery 1. The anode e is provided with a plurality ofprojections m of different lengths pointing towards the cathode. Theusual grid is indicated at cl.

The operation is as follows: The electrons emitted by the cathode areattracted by the projections m to points at varying distances from theanode, since the projections are of varying lengths. Owing to this thespace charge will be better distributed than with an anode lacking theprojections of varying lengths.

What I claim is:-

1. An electron tube comprising an electron emitting body, a grid, and ananode having projections of different lengths for receiving electrons,thereby increasing the effective anode surface upon which electrons arereceived, said projections being directed toward the same body.

2. An electron tube comprising an electron emitting body, a grid, and ananode provided with steps for receiving electrons, said steps beingdirected toward said body and enlarging the effective anode surface uponwhich electrons are received.

CHRISTOPH EDELMANN.

